Needs for reference materials

Various questions and remarks arose from the lectures given at the workshop on the role of CRMs within the EU and the production/distribution by the Institute for Reference Materials and Measurements (IRMM). Firstly, the participants felt that the 

QA/QC SYSTEMS OF THE LABOl Country Accredited/ Not certified accredited or certifit RATORIES Type of accreditation/certification system  

The inquiry has shown that the needs for CRMs/RMs are widely recognised in all sectors. It should be noted that laboratories often expressed their wishes and needs in a very unclear and vague manner which tend to confirm that information on the use and availability of reference materials is not sufficient. In addition, many laboratories declared that they do not use CRMs because they are not aware of their utility. 

An extensive list of CRMs needed by European laboratories is included in the inquiry 

Environment Food/foodstuff agriculture Health/safety Industrial products  

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The preceding chapters detail the extensive need for reference materials in the ocean sciences. This chapter focuses on what is required to produce new reference materials as well as how to encourage the use of those that already exist. 

The preparation of a reference material requires substantial planning prior to undertaking a specific project (see Box 5.1). The process begins with the definition of the material to be produced, for example, preparation of a seawater-based reference material containing the nutrient elements N03, P04, and Si(OH)4 at concentration levels appropriate to oceanic samples and certified for these constituents." Such definitions arise either from internal decisions by reference material producers (such as NIST or NRC-Canada) typically in response to perceived needs, or through external pressure on these producers from potential users. (This report, for example, explicitly identifies a number of pressing needs for reference materials for the ocean sciences.)... 

Seawater studies require certified reference materials for biologically important dissolved components such as carbon (both inorganic and organic), nutrients, and trace metals, as well as for salinity, which is hydro-graphically important. A number of the committee s key recommendations therefore explicitly address these parameters. There is also a striking need for reference materials based on particulate matrices, where many of the analytical techniques used are matrix dependent and differ markedly... 

A significant proportion of the needs for reference materials for seawater trace metal studies would be addressed by the preparation of these materials. Although the total iron concentration of these reference materials should be provided, these materials clearly will be useful for studies of other important metals such as zinc, manganese, copper, molybdenum, cobalt, vanadium, lead, aluminum, cadmium, and the rare earth elements. With careful planning, such water samples should be useful for analysis of dissolved organic substances as well. The collection sites should be chosen carefully to provide both a high and a low concentration reference material for as many metals as possible. 

A questionnaire form has been prepared to survey the analytical capabilities and research projects of laboratories of ALMERA members, and their needs for reference materials and other support. The questionnaire will be put on the ALMERA web site so that all ALMERA member laboratories can answer it on-line. 

Initial efforts by workers at the Institute for Reference Materials and Measurement (IRMM), Geel, Belgium, to produce certified reference materials for GMOs have demonstrated that the provision of suitable reference materials is not easy and that together with the development of suitable analytical methods there are many challenges to be solved ahead. The first two examples produced jointly by the IRMM in Belgium and Fluka Chemie AG in Switzerland were based on Round-Up Ready Soya and BT 176 Maize. The reference materials are needed to validate EU and Swiss regulations which permit non-GMO products to be contaminated by up to 1 % GMO material and still be accepted. 

At present, there are no widely distributed certified reference materials containing all of the radionuclides in the uranium and thorium decay series. Such reference materials are needed to calibrate instruments that make radionuclide measurements and to compare analytical results from different laboratories. The most critical need is for reference materials in the 235U decay series 231Pa, 227Ac, and 223Ra. 

It should be noted that when we used methods of measurement needing inorganic reference materials for calibration (such as flame photometry or atomic absorption spectrometry) the uncertainty due to the reference materials was considerably lower than that due to the photometric device. On the contrary, when we used a clinical reference material certified for its glucose concentration with a 10% (rel) uncertainty, this uncertainty exceeded twice the uncertainty due to the spec-trophotometric device. When we determined Mg by a spectrophotometric method with Titan Yellow, we found that the uncertainty due to the reference material was approximately twice that due the device, as we used a very accurate spectrophotometer. 

Reagents and reference materials Likely will change but should have some documentation on early characterization Continue to screen for optimal reagents Lot no. and history (notebook reference) Evaluate different reagents and identify critical reagents Determine if sufficient quantities are available and their stability for later bioanalytical needs Include C of A for reference materials in assay validation documents Keep records of source and lot no. Use optimized capture/ detection reagents Use characterized reference standard from final manufacturing process with Cof A Record all lot nos. and sources... 

Last but not least, there will surely develop a great need in future for reference materials that have been certified with respect to specific chemical species. This will be a great challenge for both producers and users of biological reference materials. In order to meet this challenge in addition to the few already existing materials projects have been implemented to arrive at a variety of reference materials for element speciation purposes (e.g. Quevauviller et al., 1993). 

As we will see later in this chapter, not only is one able to alter a nanostructure by the types of atoms and their stoichiometries, but also their 3-D arrangement. With such profound nanostmctural variety, it is no wonder that standardized toxicokinetics studies i.e., absorption, distribution, metabolism, and excretion characteristics) are still greatly lacking. For this to occur, there is a need for reference nanomaterials that would allow a systematic structure V5. toxicity assessment for various classes of nanostructures. To date, the only commercially-available reference materials are spherical nanoparticles that are used to calibrate particle-size analyzers. Such reference materials will only be possible once we have standardized protocols for the synthesis and characterization of various types of nanomaterials, an active area of investigati(Mi at the National Institute of Standards and Technology (NIST). 

In order to meet the expected industrial needs for such materials, a large scale CCVD production facility has been developed in Nanocyl S.A., with a production capacity of the order of one kg of multi-walled carbon nanotubes (MWCNTs) per hour. In a typical CCVD reactor [e.g. 4], the contact between a gaseous hydrocarbon and an appropriate solid catalyst at high temperature results in the deposition of carbon nanotubes on the catalyst. The raw product that exits the reactor is therefore expected to contain carbon nanotubes, a catalyst residue and possibly amorphous carbon. The latter two products are usually referred to as impurities. A general method to assess the amoimt of impurities in a MWNT sample is not available yet. The present work reports on the use of k ton adsorption to determine the amount of nanotubes actually present in as-synthesized sample. 

Taking into account all the above-mentioned remarks, it is evident that there is a need for the analytical control of hair-dye products notwithstanding, there are no official analytical methods to cover aU the chemicals used as hair dyes. Nevertheless, there are more than 30 published papers in which analytical methodologies to determine hair dyes in cosmetic products are proposed. However, although most of these published methods have good characteristics from an analytical point of view, most of them do not deal with the extensive number of hair dyes and mixtures currently used. The validated LC method proposed by the Institute for Reference Materials and Measurements of the Joint Research Centre of the European Commission, which aims to become a reference method for hair-dye determination deserves special notice. 

Baer recently conducted a survey of needs for improved surface analyses, with most questions on AES and XPS [137]. This survey was sent to members of the ASTM E-42 Committee and to experts participating in the work of ISO/TC 201. The survey identified specific needs for reference data, reference materials, guides for specific types of measurements on specific materials, and documentary standards. In addition, there were recommendations for additional interlaboratory comparisons and educational opportunities (topical symposia and workshops) on particular aspects of AES and XPS measurements. 

Ether - Starting fluid (works great - Quaaaaack ) 2. Home made mercuric acetate (Now this stuff can be special ordered from ones chem supplier but there s a delay, may look funny - Quaaaaack , and is more expensive. So what is the solution to this Make it yourself Its easy, quantitative, and cheaper. Strike mentions this in the book and points ducks to a reference. Follow the EXACT same procedure for Mercuric Propionate except use glacial acetic acid...quack ). You ll need to use 20 to 25% more of the home brew mercuric acetate since it is a little contaminated with acetic (ducks can t get it totally dry without a vacuum oven). 3. NaOH washed Brazillian is fine Quack No need to purify further for starting material ... 

For example, if a carbonaceous sample (S) is examined mass spectrometrically, the ratio of abundances for the carbon isotopes C, in the sample is Rg. This ratio by itself is of little significance and needs to be related to a reference standard of some sort. The same isotope ratio measured for a reference sample is then R. The reference ratio also serves to check the performance of the mass spectrometer. If two ratios are measured, it is natural to assess them against each other as, for example, the sample versus the reference material. This assessment is defined by another ratio, a (the fractionation factor Figure 48.2). 

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